PROBLEMS AND CERTAINTIES IN THE EXPERIMENTAL SIMULATION OF THE SEISMIC RESPONSE OF MDOF STRUCTURE

A critical discussion of problems in the experimental simulation of se ismic loads on civil structures is presented, primarily addressing iss ues concerning the choice of test method, (dynamic, static, or pseudod ynamic), the selection of appropriate ground motions, and the method o f controlling tests, (in force control, displacement control, or a com bination of the two). Particular attention is given to the problem of the interaction between applied actions and observed response in struc tures with multiple degrees-of-freedom. Three examples of recent struc tural tests performed at the Universities in Pavia (Italy), California (San Diego), and Illinois (Urbana-Champaign) are cited to illustrate hybrid tests in which novel approaches have been used to maximize the utility of data from tests on multi-degree-of-freedom structures.